Method and apparatus for measuring a particle diameter of foam on a malt alcoholic drink

ABSTRACT

A method and apparatus for measuring the particle diameter of foam on a malt alcoholic drink, which can detennine the quality of the foam of the malt alcoholic drink objectively, are provided. The apparatus for measuring the particle diameter of foam on a malt alcoholic drink according to the present invention includes a laser light source for irradiating a linear laser beam onto the surface of a foam layer created on a malt alcoholic drink, an imaging device for imaging a laser line reflected on the surface of the foam layer to obtain an image of the laser line, and a calculating device for obtaining edge information of the laser line from the image of the laser line to calculate the particle diameter of foam in the foam layer based on the edge information.

TECHNICAL FIELD

The present invention relates to a method for measuring a particlediameter of foam on a malt alcoholic drink and an apparatus formeasuring the particle diameter of foam on a malt alcoholic drink.

BACKGROUND ART

As a malt alcoholic drink such as beer and low-malt beer is poured intoa vessel at the time of drinking, a foam layer is created on the surfaceof the malt alcoholic drink. The property of the foam layer is oneimportant factor indicating the quality of the malt alcoholic drink.

The property of the foam layer is represented by the degree of foaming,the thickness of the foam layer, the continuity of the foam layer (foamretention), the size of the particle diameters of foam, and the adhesiveproperty of foam to the vessel, etc., and is a parameter for evaluatingeach foam layer objectively.

With respect to the particle diameter of foam, a foam layer composed offine and uniform foam particles is called as creamy, continuous, andhigh quality foam to the eye. On the other hand, large and coarse foamparticles that are created immediately after pouring into a vessel andcollapse rapidly on the upper layer in a foam layer have no continuity.When such large and coarse foam particles are relatively abundant, theoverall continuity of the foam layer is small and it is not a creamyfoam. Accordingly, the property of created foams can be determined bymeasuring the particle diameter of the foam. The measure of the particlediameter of foam not only determines the property of foam on a maltalcoholic drink such as beer and low-malt beer, but also can be appliedto determine whether or not very fine and creamy foam particles havebeen created, for example, in a foam layer of whipped cream.

However, no measuring method capable of appropriately measuring theparticle diameter of foam on malt alcoholic drinks has been establishedand the measure of the particle diameter of foam has to depend on visualevaluation in the present circumstances, so that it is difficult toobtain an accurate measurement of the particle diameter of foam.

DISCLOSURE OF THE INVENTION

One of the objects of the present invention is to provide a method formeasuring a particle diameter of foam on a malt alcoholic drink, whichcan determine the quality of the foam of the malt alcoholic drinkobjectively.

Another object of the present invention is to provide an apparatus formeasuring a particle diameter of foam on a malt alcoholic drink, whichcan determine the quality of the foam of the malt alcoholic drinkobjectively.

One of the objects can be achieved by a method for measuring a particlediameter of foam on a malt alcoholic drink, which includes the steps ofirradiating a linear laser beam onto a surface of a foam layer createdon a malt alcoholic drink, imaging a laser line reflected on the surfaceof the foam layer by an imaging device to obtain an image of the laserline, and obtaining edge information of the laser line from the image ofthe laser line to calculate a particle diameter of foam in the foamlayer based on the edge information.

In the method for measuring a particle diameter of foam on a maltalcoholic drink, preferably, the linear laser beam is obliquelyirradiated onto the surface of the foam layer and the laser line isimaged from a position in a direction perpendicular to the surface ofthe foam layer.

Also, one of the objects can be achieved by an apparatus for measuring aparticle diameter of foam on a malt alcoholic drink, which includes alaser light source that irradiates a linear laser beam onto a surface ofa foam layer created on a malt alcoholic drink, an imaging device thatimages a laser line reflected on the surface of the foam layer to obtainan image of the laser line, and a calculating device that obtains edgeinformation of the laser line from the image of the laser line tocalculate a particle diameter of foam in the foam layer based on theedge information.

Other objects and features of the present invention will become moreapparent from the following detailed description illustrated inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an apparatus for measuring the particlediameter of foam on a malt alcoholic drink according to the presentinvention.

FIG. 2 is a diagram illustrating the principle of a method for measuringthe particle diameter of foam on a malt alcoholic drink according to thepresent invention.

FIG. 3 is a drawing that illustrates one example of a laser line imageobtained by imaging the laser line reflected on the surface of a foamlayer by a CCD camera.

FIGS. 4A-4D are diagrams showing concavity and convexity observed onedge portions of a laser line.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention are illustrated in detail inconjunction with drawings bellow.

First, an apparatus for measuring the particle diameter of foam on amalt alcoholic drink according to the present invention is illustratedusing FIG. 1. The apparatus for measuring the particle diameter of foamon a malt alcoholic drink according to the present invention is also anapparatus for determining the quality of foam on a malt alcoholic drinkand, for simplicity, is referred to as a foam quality-evaluatingapparatus below. Also, an example of beer employed as the malt alcoholicdrink is illustrated.

A foam quality-evaluating apparatus shown in FIG. 1 is composed of abeer-pouring-out device 10, a data processing device 6, and a dataoutput device 7. Herein, the beer-pouring-out device 10 includes aturntable 2, a beer-pouring-out mechanism 3, a CCD camera 4, and alinear laser light source 5. Also, the turntable 2 supports a vesselsuch as a test glass 1 and can move the test glass 1 to a position atwhich beer is poured out and a position at which foam on beer can beimaged. Further, the beer-pouring-out mechanism 3 holds a beer bottleand pours out beer into the test glass 1. An imaging device such as theCCD camera 4 images foam created on the surface of beer from above.Additionally, the linear laser light source 5 irradiates a linear laserbeam into the test glass 1. The laser light source 5 is composed of, forexample, an aspheric lens and a rod lens. As a laser light source foremitting such a linear laser beam, for example, LM10 produced by FMLaser Tec. Co., Ltd. can be used. A linear laser beam with a line widthequal to or less than 1 mm can be obtained by using the laser lightsource.

Also, the foam quality-evaluating apparatus shown in FIG. 1 includes apersonal computer 6 with a monitor and a printer 7. Herein, the personalcomputer 6 with a monitor sets and controls the operation of thebeer-pouring-out device 10 and processes obtained measurement data, andthe printer 7 prints out the measurement data.

Next, the principle of a method for measuring the particle diameter offoam on beer being a malt alcoholic drink according to the presentinvention is illustrated using FIG. 2. First, in the foamquality-evaluating apparatus, beer is poured into the test glass 1 fromthe beer-pouring-out mechanism 3 and the turntable 2 is rotated so thatthe test glass 1 is moved to a position at which foam on the beer can beimaged. At this time, a foam layer has been created on the surface ofthe beer poured into the test glass 1. Then, a linear laser beam isirradiated from the laser light source 5 to the beer poured into thetest glass 1 and the beer poured into the test glass 1 is imaged fromabove the test glass 1 using the CCD camera 4. For more detail, thelinear laser beam is obliquely irradiated on the surface of the foamlayer created on the beer poured into the test glass 1 from the laserlight source 5 located obliquely upward relative to the test glass 1 anda laser line is reflected on the surface of the foam layer. The laserline reflected on the surface of the foam layer is imaged by the CCDcamera 4.

As shown in the upper part of FIG. 2, as the beer poured into the testglass 1 is observed from the side over time, the foam layer created onthe surface of the beer poured into the test glass 1 collapses overtime, so that the surface of the foam layer (foam surface) falls from aninitial foam surface S_(A) to a foam surface S_(B). At this time, thelaser line reflected on the surface of the foam layer moves fromposition A to position B.

Also, as shown in the lower part of FIG. 2, as the beer poured into thetest glass 1 is observed from the top surface over time, the laser linereflected on the surface of the foam layer moves from position α toposition β while the height of the foam surface falls from the height ofthe foam surface S_(A) to the height of the foam surface S_(B). That is,when the foam surface is at the height of S_(A), the laser line is atthe position of α, and when the foam surface is at the height of S_(B),the laser line is at the position of β.

FIG. 3 shows one example of a laser line image obtained by imaging alaser line reflected on the surface of a foam layer by a CCD camera. Asshown in FIG. 3, a linear laser beam is emitted from the laser lightsource 5 and a whitely shining linear laser line with a width ofapproximately 1 mm is reflected on the surface of the foam layer on thebeer. Concavity and convexity formed by foam particles are observed onedge portions of the laser line.

FIGS. 4A-4D are schematic diagrams for illustrating a laser linereflected on the surface of a foam layer on beer in detail, which showconcavity and convexity observed on edge portions of the laser line.Herein, it is assumed that foam particles having equal particlediameters are aligned along both edge portions of a laser line reflectedon the surface of a foam layer on beer. FIG. 4A shows the alignment offoam particles having relatively large particle diameters, FIG. 4C showsthe alignment of foam particles having relatively small particlediameters, and FIG. 4B shows the alignment of foam particles havingintermediate particle diameters. Additionally, FIG. 4D is across-sectional view along the m-m′ directions of one of foam particlespresent on edge portions of the laser line shown in FIG. 4A. That is,when the linear laser beam from the laser light source 5 is obliquelyirradiated onto the surface of the foam layer on the beer as shown inFIG. 4D, the concavity and convexity are formed on the edge portions ofthe laser line by the foam particles aligned on the surface of the foamlayer on the beer in FIGS. 4A-4C. Such laser line having concavity andconvexity on the edge portions is imaged by the CCD camera 4. Then, anobtained laser line image as shown in FIG. 3 is image-processed by thepersonal computer 6 with a monitor so as to define the concavity andconvexity on the edge portions of the laser line.

As the brightness of the laser line image is detected as imageprocessing for the laser line image by the personal computer 6 with amonitor, the profiles of foam particles present on edge portions of thelaser line image can be observed. That is, bright portions in the laserline image indicate the linear laser beam and dark portions on the edgeportions of the laser line image indicate the foam particles. Herein,the particle diameter of the foam can be calculated by evaluating thesize of the dark portion on the edge portions of the laser line image.For example, a signal of the image with respect to the edge portions ofthe laser line is binarized while a certain threshold value of thebrightness is set, so as to distinguish the bright portions from thedark portions on the edge portions of the laser line. At this time, thedefinite profiles of the concavity and convexity caused by the foamparticles on the edge portions of the laser line can be detected byselecting the threshold value of the brightness appropriately, as shownin FIGS. 4A, 4B, and 4C. Since a two-dimensional waveform with respectto the brightness of the obtained laser line image reflects how largethe particle diameter of foam is, various techniques for measuring andanalyzing the waveform can be applied in order to digitize the particlediameter of foam. For example, a reference gage is prepared in an imageprocessing software and the amplitudes of the two-dimensional waveformare each measured by the gage, so as to determine the diameter of theindividual foam particles directly.

Also, the profiles of the concavity and convexity on the edge portionsof the laser line are perceived as the collection of picture elements onan image-processing screen. In an obtained image from above the glass,the respective picture elements that form the profile correspond to theinformation of the height viewed from the side as shown in FIG. 2, whichcan be obtained through digitization. The dispersion of the informationof the heights of all picture elements that form the profile reflectsthe size of the foam particle that causes the formation of the concavityand convexity and the sizes of the foam particles can be compared by thecomparison of statistics (e.g. deviations or dispersions) as thedispersion degrees of the height information. The image processing forthe laser line image and the evaluation of the particle diameter of thefoam are performed in a processing unit of the personal computer 6 witha monitor in the foam quality-evaluating apparatus shown in FIG. 1.

As described above, in the foam quality-evaluating apparatus as shown inFIG. 1, beer is poured into the test glass 1 using the beer-pouring-outapparatus 10, a linear laser beam from the laser light source 5 isirradiated onto a foam layer created on the beer, a laser line reflectedon the surface of the foam layer is imaged by the CCD camera 4, anobtained laser line image is image-processed by the personal computer 6with a monitor so as to obtain information for the profile of edgeportions of the laser line (edge information), and the particle diameterof foam in the foam layer created on the beer can be determined based onthe information of the profile. Additionally, as shown in FIG. 2, thedegree of foam retention of beer can be also determined by observing afoam layer created on the beer using the foam quality-evaluatingapparatus as shown in FIG. 1, immediately after pouring the beer intothe test glass 1 and after a predetermined time has passed since thebeer is poured. Also, the number of concavities and convexities on edgeportions of a laser line, that is, the number of foam particles on theedge portions of the laser line can be digitized and the size of thefoam particles can be also digitized by obtaining information for theprofile of the edge portions of the laser line as described above.

Although the preferred embodiments of the present invention aredescribed above in detail, the present invention is not limited to theabove-mentioned embodiments and the embodiments can be improved andmodified within the scope of the claims.

INDUSTRIAL APPLICABILITY

As described above, the particle diameter of foam on a malt alcoholicdrink can be measured to determine the quality of the foam on the maltalcoholic drink objectively, using a method for measuring the particlediameter of foam on a malt alcoholic drink and an apparatus formeasuring the particle diameter of foam on a malt alcoholic drink,according to the present invention.

1. A method for measuring a particle diameter of foam on a maltalcoholic drink, characterized by comprising the steps of: irradiating alinear laser beam onto a surface of a foam layer created on a maltalcoholic drink; imaging a laser line reflected on the surface of thefoam layer by an imaging device to obtain an image of the laser line;and obtaining edge information of the laser line from the image of thelaser line to display a particle diameter of foam in the foam layerbased on the edge information.
 2. The method for measuring a particlediameter of foam on a malt alcoholic drink as claimed in claim 1,wherein the linear laser beam is obliquely irradiated onto the surfaceof the foam layer, and the laser line is imaged from a position in adirection perpendicular to the surface of the foam layer.
 3. The methodfor measuring a particle diameter of foam on a malt alcoholic drink asclaimed in claim 1, wherein said edge information comprises informationwhich determines a concavity and convexity of foam particles on edgeportions of said laser line so as to allow the particle diameter of thefoam particles to be determined.
 4. An apparatus for measuring aparticle diameter of foam on a malt alcoholic drink, which comprises: alaser light source that irradiates a linear laser beam onto a surface ofa foam layer created on a malt alcoholic drink; an imaging device thatimages a laser line reflected on the surface of the foam layer to obtainan image of the laser line; and a calculating device that obtains edgeinformation of the laser line from the image of the laser line tocalculate a particle diameter of foam in the foam layer based on theedge information.
 5. The apparatus for measuring a particle diameter offoam on a malt alcoholic drink as claimed in claim 4, wherein said edgeinformation comprises information which determines a concavity andconvexity of foam particles on edge portions of said laser line so as toallow the particle diameter of the foam particles to be determined.